Water-tube boiler



Dec. 15, 1964 SOJXN MATSUMOTO WATER-TUBE BOILER Filed Oct. 24, 1962 INVENTOR SOJIN MATSUMOTO BY WM ATTORNEYS United States Patent 3,i-l,l79 VJi KTEP-TUEE i3 ELER Satin Matsumoto, 54d Qokuruiruji, Kamalrura'shi, Kanagawa-lren, .lapau Filed Get. 24, 1%2, Ser. No. 232,315 1 Claim. 122-3231) The present invention relates to a low pressure watertube boiler, and, in particular, to a low pressure steam boiler having a plurality of vertical semi-circular water tubes and inclined spiral water tubes fixed around a vertical convection cylinder.

The water tube boilers composed of a plurality of vertical convection cylinders and inclined spiral water tubes connecting the cylinders with each other are already known. But, such known boilers cannot be made in small-sized boilers as they use many convection cylinders requiring considerable space.

It is, therefore, an object of the present invention to obtain a water-tube boiler of comparatively small size using one vertical convection cylinder, suitable for household, laundry and public bath uses.

Another object of the present invention is to provide a boiler possessing, though small in size, comparatively great efiiciency both in operation and heat absorption by connecting upper and lower ends of a vertical convection cylinder together with a plurality of vertical semi-circular water tubes as well as by connecting each side of said cylinder with a plurality of inclined spiral water tubes.

Further objects and advantages of this invention will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate one embodiment of the invention and in which similar numerals refer to similar parts throughout the several views. In the drawings:

FIG. 1 is a view in vertical cross section of the boiler of the present invention, the view being taken along the line 1-4. of FIG. 2, assuming the boiler is complete.

FIG. 2 is a view in horizontal cross section, being taken along the line 22 of FIG. 1, assuming the boiler is complete.

FIG. 3 is an enlarged side elevation of the stand convection cylinder of the device shown in FIG. 1, illustrating arrangements of vertical and slant water tubes on said cylinder.

Referring now to FIG. 1, the boiler has a cylindrical casing 3 having around the upper interior portion of said casing, a circular jacket or preheating chamber 4. Within the cylindrical casing 3, a closed end convection cylinder 5 is positioned vertically. Said convection cylinder 5 is vertically partitioned into two equal parts by the connection to the inner wall of the cylinder of a central bafr'lc plate 6, leaving a space both at the top and bottom of said baffle plate between the upper end of said baffle plate and upper wall of the cylinder and between the lower end of said bafile plate and lower wall of the cylinder respectively. Besides, on both sides of the lower part of said central bafiie plate 6 and at two places dividing the cylinder into four parts, there are provided two angular auxiliary bathe plates 7, 7 the uppermost ends of which are connected to and extend horizontally from said cylinder towards, but spaced from the lowermost end of the central baffle plate 6.

The upper and lower parts of the outer wall of the convection cylinder 5 are vertically connected with each other by a plurality of vertical semi-circular water tubes 8, 9, l0 and 11 respectively connecting at openings (1 with (1 b with b 0 with c and d with a which are, shown in PEG. 3, arranged zigzag in several columns and several lines so as to allow each of these water tubes to equally receive the heat from furnace 29. The vertical semi-cirice cular water tubes project radially from and around the cylinder.

A plurality of further water tubes l2, l3 and 14- are provided in the space between the innermost semi-circular water tubes ll and cylinder wall 5, connecting one side of the baflie plate 6 with the other, as shown in "FIG. 2. These water tubes i2, 13 and i l are not strictly horizontal, but slightly inclined to the left as shown in FIG. 3, thereby forming a. helical water tube with the lower left and higher right on the whole. Also, the length of these tubes are diverse, the central one 12 being longest while other ones being gradually shortened with approach to the uppermost and lowermost shortest tubes 13 and 1d attempting to heat equally all of these tubes by the flames coming from the bottom of the boiler.

The water is supplied to the boiler from a supply tank 15 at given intervals of a limited time through the jacket or preheating chamber 4 where there is already existing a lukewarm water of about Q. warmed up during the preceding operation, and from where said lukewarm water is supplied to the bottom of the stand convection cylinder 5 through the conduit pipe 16 by operation of a pump 17, to the extent of filling the cylinder with water up to the water level 18, the evaporation surface which is located under the upper wall of the cylinder at some intervals. The steam generated on the evaporation surface 18 is first kept in a steam receiver 21 and is then exhausted therefrom by means of a valve 22 for various uses as occasion demands. To the bottom wall of the stand convection cylinder 5, a drain pipe 24 is also connected for taking out the hot water for necessary uses or for exhausting all the water after termination of operation. Surplus heat gas is discharged from chimney 23.

To use the present boiler, the pie-heated water in the jacket 4 i first supplied to the vertical convention cylinder through the conduit pipe to as stated above, until the water surface thereof reaches the fixed water level 13, thereby filling said cylinder, vertical are water tubes 8, 9, it and Ill and inclined water tubes 12, i3 and 14 with the water. When the combustion of the fuel in the burner ill} in furnace 19 is recommenced, the lower parts of the cylinder and water tubes are most strongly heated.

Then the water existing in the lower part of the vertical water tubes 8, 9, iii and 11 becomes less dense in consequence of absorption of steam generated in the water by boiling, and begins to rise. The rising hot water mixing with the colder water in the upper part of the tube flows into the upper part of the stand convection cylinder 5 and goes down after colliding against the central bafile plate 6. Most of the descending water current flows into the lower ends of the semi-circular water tubes passing around the lower ends of angular balfie plates 7, 7, as the lower ends of said angular battle plates are both located a little higher than that of the central bafile plate 6. Two semicircular water currents thus arise on both sides of the baffle plate 6, the current on left side circulating clockwise and that on right side counterclockwise, which naturally increases their absorption of heat.

It is the action of the inclined spiral water tubes 12, 13 and 14 which are heated simultaneously with the vertical water tubes, that causes a convection between said two currents on both sides of the central baffle plate 6 connecting them with each other. That is to say, the water in said inclined tubes begins to rise obliquely from the left to the right with the increase of heating, and the water in the left half of the vertical convection cylinder 5 travels toward the rig-ht half thereof through said inclined tubes or by flowing over the upper most end of said bathe plate 6, since; and the temperature of the water in the right half is always higher than that in the left half. By this thermal difference, the Water in these two halves is forced to flow clockwise along and around the central 3 baffie plate 6 climbingover the uppermost end of the baffle plate and passing under the lowermost end thereof, and, in the meanwhile, the water in the inclined water tubes 12, 13 and 14 which are arranged substantially at right angles to the advancing direction of heat gas is strongly heated and boiled and a rapid generation of steam is obtained. The present invention has thus a high heat absorption factor raising natural and smooth conventions at the same time in three places, namely in left and right halves of the vertical convection cylinder 5 where there occurs a vertical semi-circular convection in each half of said cylinder by means of the vertical water tubes 8, 9, 10 and 11 and in the middle of the cylinderiwhere there occurs a susbtantially horizontal convection by means of the inclinedwater tubes 12, 13 and 14 without causing any whirlpool.

In the drawing and specification, there has been set forth .a preferred embodiment of the invention, but any larger boiler can be constructed in assembling several of the present device in a cylindrical casing.

It is claimed:

A water boiler for generating low pressure steam or for supplying hot water, comprising a boiler casing, an annular water pre-heating jacket provided around the upper portion of the interior of said boiler casing, a vertical convection cylinder in said boiler casing, a pipe connecting said water pre-heating jacket to said convection cylinder, a vertical diametrical 'bafile plate coaxially maintained in said convection cylinder, two symmetrical angu: lar auxiliary baffle plates each mounted extending from said cylinder towards the vertical side of the lower part of said bafile plate and spaced from said vertical baffle plate, the lower ends of said angular baffle plates being located a little higher in said cylinder than the lower end of said vertical vbafile plate, a plurality of vertical semicircular water tubes positioned exteriorly of said convection cylinder and connecting vertically and radially the upper and lower parts of said convection cylinder with each other, and a plurality of inclined spiral water tubes in the space between the innermost semiacircular water tubes and said convection cylinder and extending through said convection cylinder interconnecting the spaces formed between said vertical batfie plate and said convection cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Penney Mar. 24, 1908 FOREIGN PATENTS Switzerland Sept. 16, 1935 

